whats with LLs not allowing mirrors?

[Mateusz]

Originally posted by Wazza
This is NOT my opinion

Some LL owners believe that by being on the folder "default" index.html (or other as specified) page they will gain a boost in the search engines. This is the primary reason why LLs demand index.html listings.

I could go on - but I'm not in the mood for a barney atm...

I guess it's not faith but facts - each big guy (LOL) says he get more sales and site gets better (and constant) SE listeing if he don't use mirrors pages at all... so thats the reason of this rule.
It looks 'lil bit irracionally but I trusted them try working this way since some time.. So far I see no results but I belive it will come..